With the exploitation of onshore wind resources becoming increasingly saturated, the development of wind power generation has gradually shifted to offshore areas. However, the offshore wind power generation is facing challenges such as high cost, difficult maintenance, bad environment and so on.
In order to reduce the investment cost per kilowatt of offshore wind power generation, wind turbines gradually tend to have large size. However, increasing the single-machine power will increase heat generation of sub-components and increase the number of components requiring active heat dissipation.
Currently, the heat generating components in a high-power wind turbine are often equipped with independent heat dissipation systems. This decentralized cooling manner involves not only high costs, but also many trouble spots, and further, the high humidity offshore environment may be apt to cause condensation, resulting in short circuit in the electronic elements. In addition, the offshore wind turbine maintenance is difficult, the frequency of offshore maintenance should not be too high, and thus the system is required to have a high reliability.
In view of this issue, the invention patent application with publication No. CN105179180A discloses a cooling system for a bottom of a tower of a high-power offshore wind turbine, in which, a heat sink for an inverter and a heat sink for a box transformer are integrally designed and share one heat sink system, and the heat sink system is placed outside the tower, further, a closed cycle air path system is arranged in the spaces of the three layers of the tower which is provided for placing electric cabinets, to control the temperature and humidity in the spaces of the three layers at a lower part of the tower.
However, in this technical solution, the heat sinks are externally disposed, which takes more time in hoisting and takes up more space, and especially for an offshore wind turbine, it may occupy more space of a base external platform, thus increasing construction costs of the base external platform. Moreover, since the heat sinks are externally disposed, it is further required to cut more holes in the tower for laying water inlet pipes and water outlet pipes of the water-cooling heat sink and cables for providing power to water-cooling fans. In addition, this technical solution can only control the temperature and humidity in the closed spaces in the three layers of the lower part of the tower, and can not adjust the temperature and humidity of other spaces in the tower.
Furthermore, although a closed cycle air loop is provided in the spaces of the three layers at the bottom of the tower, in fact, operation and maintenance personnel need to enter the spaces to perform operations. When personnel enter and exit, it is inevitably to introduce external air (with salt spray and high humidity) into the spaces, and in addition, to satisfy the survival needs of personnel in their work, the space cannot be completely sealed in the operation of personnel (since the personnel need oxygen in breathing), therefore, it is hard to control the air cleanliness of the closed cycle air path system in the three layers.
Therefore, a technical issue to be addressed by the person skilled in the art is to overcome the above disadvantages of the tower bottom cooling device for the wind turbine.